An explosive motor is usually provided with a supercharger for compressing air before air enters a cylinder so as to improve efficiency and output power, and accordingly more air is sucked for combusting more fuel under the condition of a same cylinder volume, thereby facilitating the purpose of increasing the power.
Conventional engine superchargers in general use employ mechanical supercharging, turbocharging and the like. Mechanical supercharging comprises centrifugal mechanical supercharging, spiral supercharging, Roots supercharging and the like, possesses advantages of work reliability, good linear following feature and excellent performances when an engine operates at a low speed and the like because the engine is directly used for driving a supercharger and further high-density air is sent into a cylinder for improving output power of the engine. However mechanical supercharging has the disadvantages that supercharging effect is not ideal, noise is relatively large at a high-speed stage, and the like.
An application CN201010593788.3 “friction wheel high-speed suspension shaft centrifugal supercharger” applied in 2010 by the same inventor, solves the problems that a conventional mechanical supercharger is large in volume and low in efficiency and the rotation speed is difficult to improve, and possesses advantages of simple structure, preparation easiness and the like by researching and designing a novel suspension mainshaft and a matched friction wheel structure. However, through engineering application in subsequent several years and actual tests, the centrifugal supercharger still has the following defects or disadvantages: 1) the centrifugal supercharger employs three belt wheels for respectively transmitting engine power to friction wheels as first-order transmission, but once a part of one belt wheel is unstressed during loading, empty load is formed between the belt wheel and the friction wheel, and may cause increase of the sliding ratio of a central shaft and reduction of the transfer efficiency; 2) since a plurality of belt wheels are demanded for executing transmission, the loading orientation is greatly limited when the belt wheels are installed on an automobile engine, and therefore it is difficult to design and install the belt wheels during actual operation; 3) the friction wheel in the centrifugal supercharger, as one of main core components, is composed of a wheel center, a rubber ring, a steel wheel sleeve and a magnetic ring, and a bench test proves that the rubber ring generates difficultly-recovered deformation or even is broken and causes periodic slip between the friction wheel and a center shaft or failure of the whole supercharging system because of high-frequency stress resistance and drawing force after the friction wheel runs for a relatively long period since the rubber bears rotation pressure and circumferential drawing force during rotation in a bench test, which are especially obvious after the rotation speed is improved; and 4) at present a fan is employed for cooling the friction wheel, which is suitable when the transmission efficiency of the supercharger is low or middle, but after the transmission efficiency is improved to a relatively high degree, the cooling effect is limited and is guaranteed only by improving the power of the fan, and accordingly the load of the whole machine is improved and the system noise is substantially increased.